This invention relates to a special kind of sports bicycle called a BMX or Freestyle bike. Typically, these have a low profile with wheel diameters of 20 inches or less and are extremely rugged. They are used for sprinting, racing, and a wide variety of trick maneuvers, such as climbing an inclined ramp and dropping to a track below, riding or balancing the bike while tilted upright on its rear wheel, riding or coasting while seated or standing on the handlebar cross-bar, or with the rider's feet or hands supported on tires, handlebars, and various frame portions which may be added as accessories or provided as integral original parts of the frame.
As examples, some front forks have horizontal stub shafts. A step-like rear extension of the top tube provides a standing platform beneath the seat in some of these bikes. Bolted standing platforms are provided as add-on accessories which may be secured to one or both ends of the rear axle or to the end portions of the chain stay tubes.
One favorite standing platform for freestyle performers is provided at the top of the seat stay tubes just behind and below the seat. However, because the rear caliper brake typically is secured to the top of a bridge interconnecting the seat stay tubes at that location, the upstanding brake and its actuating cable can interfere with the performer's feet and severely limit the standing space available.
Examples of attempts to provide uncluttered, standing room behind and below the seat include providing a relatively free standing area on the seat stay tubes between the rear brake and the seat mast as shown in the GT Pro Series and Redline BMX bikes illustrated on pages 6, 7, and 8, 9 of the March, 1986 BMX Action Magazine.
Other examples involve extending the top tube rearwardly beneath the seat to provide a rear standing platform above and clear of the rear brake calipers. Such standing platforms are shown on the Kanahara and Hutch BMX bikes illustrated respectively on pages 23 and 47 of the March, 1986 BMX Action Magazine.
In an attempt to increase the clear footroom on the top of the seat stay tubes, in some models, the rear caliper brake has been secured on the underside of the seat stay tubes. While an improvement, it has not been entirely satisfactory because the performer's foot could overhang the seat stay tube, engage the caliper brake arm, and interfere with operation of the brake.
Other favorite rear standing platforms or support surfaces include axial stub extensions on or near the rear axle. These may be permanently secured by welding, or screwed or bolted on as optional accessories, examples of which are shown in advertisements appearing on pages 8, 12, 37, 39, and 42 of Freestyle Magazine for April, 1986.